Characterization of lymphocyte subpopulations which exhibit enhanced DNA synthesis in vitro in DNFB contact sensitive guinea-pigs.

Different lymphocyte subpopulations were prepared from lymph nodes and spleen obtained from 2.4-dinitrofluorobenzene/Freund's complete adjuvant (DNFB/FCA) sensitized guinea-pigs. The capacity to react in vitro to secondary antigenic (dinitrophenyl-modified syngeneic macrophages, DNP-MO) stimulation by an increased DNA synthesis, appeared to be restricted to those T cells which lack receptors for IgG-Fc (T gamma -). We confirmed the existence in this species of an IgG-Fc receptor-positive T-cell subset, which is particularly represented in the spleen (up to 56%). These T gamma + cells apparently are not of monocyte lineage as they show strong PHA-responsiveness and a lack of non-specific esterase staining, whereas the majority of these cells form RRBC-rosettes. Neither B nor T gamma + cells appeared to act as suppressor cells in the secondary DNP-MO-driven proliferative response.